Modeling the ACVR1R206H mutation in human skeletal muscle stem cells.

Abnormalities in skeletal muscle repair can lead to poor function and complications such as scarring or heterotopic ossification (HO). Here, we use fibrodysplasia ossificans progressiva (FOP), a disease of progressive HO caused by ACVR1R206H (Activin receptor type-1 receptor) mutation, to elucidate how ACVR1 affects skeletal muscle repair. Rare and unique primary FOP human muscle stem cells (Hu-MuSCs) isolated from cadaveric skeletal muscle demonstrated increased extracellular matric (ECM) marker expression, showed skeletal muscle-specific impaired engraftment and regeneration ability. Human induced pluripotent stem cell (iPSC)-derived muscle stem/progenitor cells (iMPCs) single-cell transcriptome analyses from FOP also revealed unusually increased ECM and osteogenic marker expression compared to control iMPCs. These results show that iMPCs can recapitulate many aspects of Hu-MuSCs for detailed in vitro study; that ACVR1 is a key regulator of Hu-MuSC function and skeletal muscle repair; and that ACVR1 activation in iMPCs or Hu-MuSCs may contribute to HO by changing the local tissue environment.

Localized chondro-ossification underlies joint dysfunction and motor deficits in the Fkbp10 mouse model of osteogenesis imperfecta.

Osteogenesis imperfecta (OI) is a genetic disorder that features wide-ranging defects in both skeletal and nonskeletal tissues. Previously, we and others reported that loss-of-function mutations in FK506 Binding Protein 10 (FKBP10) lead to skeletal deformities in conjunction with joint contractures. However, the pathogenic mechanisms underlying joint dysfunction in OI are poorly understood. In this study, we have generated a mouse model in which Fkbp10 is conditionally deleted in tendons and ligaments. Fkbp10 removal substantially reduced telopeptide lysyl hydroxylation of type I procollagen and collagen cross-linking in tendons. These biochemical alterations resulting from Fkbp10 ablation were associated with a site-specific induction of fibrosis, inflammation, and ectopic chondrogenesis followed by joint deformities in postnatal mice. We found that the ectopic chondrogenesis coincided with enhanced Gli1 expression, indicating dysregulated Hedgehog (Hh) signaling. Importantly, genetic inhibition of the Hh pathway attenuated ectopic chondrogenesis and joint deformities in Fkbp10 mutants. Furthermore, Hh inhibition restored alterations in gait parameters caused by Fkbp10 loss. Taken together, we identified a previously unappreciated role of Fkbp10 in tendons and ligaments and pathogenic mechanisms driving OI joint dysfunction.

Heterotopic Ossification After Prestige-LP Cervical Disc Arthroplasty Is Related to Insufficient Sagittal Coverage of the Endplate By the Prosthesis.

BACKGROUND Heterotopic ossification (HO) is a major complication after cervical disc arthroplasty (CDR) that has attracted the attention of spine surgeons. There remains a great deal of controversy regarding the surgical risk factors. The present study investigated the correlation between insufficient sagittal coverage of the prosthesis-endplate and HO after CDR and explored strategies to prevent it. MATERIAL AND METHODS We included 73 patients who underwent Prestige-LP arthroplasty. Patients were divided into HO and non-HO groups. Related data, including radiological, clinical information, were collected. HO was graded using the McAfee classification. Analysis was performed to correlate HO to the surgical segmental range of motion (ROM) at last follow-up. To evaluate the insufficient sagittal coverage of the prosthesis-endplate and other factors for developing HO, receiver operating characteristic (ROC) curves were analyzed for insufficient sagittal coverage. RESULTS Among 73 patients, 24 patients had HO at the last follow-up (HO incidence: 32.9%). The ROM in the HO group was significantly lower (P<0.001). The insufficient sagittal coverage of the upper and lower prosthesis-endplate, the height of intervertebral space, and the preoperative and postoperative ROM were related to HO (P<0.05). Multivariate logistic regression analysis showed that only insufficient sagittal coverage of the upper prosthesis-endplate was related to HO (P=0.023), and ROC curve analysis revealed that HO was more likely to occur with insufficient sagittal coverage distance ≥2.5 mm. CONCLUSIONS HO after CDR causes a reduction in ROM, the occurrence of which is associated with insufficient sagittal coverage of the prosthesis-endplate. HO was more likely to occur with insufficient sagittal coverage distance ≥2.5 mm.

Diverse manifestations of a sickle cell crisis.

We describe the case of a 21-year-old man with a background of sickle cell disease (SCD) who was on acute presentation in a sickle cell crisis required immediate intensive care admission with red blood cell exchange and ventilatory support. He had right frontal lobe infarcts and extensive bilateral deep white matter lesions most likely secondary to fat embolism. Inpatient investigations demonstrated a patent foramen ovale, explaining the route of spread of the fat embolus. He then had a transcatheter closure of the atrial defect. The patient needed prolonged inpatient rehabilitation. He was discharged from hospital in a wheelchair secondary to severe lower limb neurology and bilateral knee heterotopic ossification. He lives with the possibility of early onset dementia and cognitive decline, requiring constant care. The case highlights the multiple manifestations of SCD and their diverse and debilitating consequences.

[Heterotopic ossifications after COVID-19 pneumonia]. / Heterotope ossificatie na een covid-19-pneumonie.

COVID-19 patients admitted to the Intensive Care Unit may develop painful range of motion restrictions of the large joints due to heterotopic ossifications. Here we describe two patients who developed restricted and painful passive and active mobility of the hips, shoulders and elbows after mechanical ventilation because of respiratory failure due to COVID-19 pneumonia. Conventional radiography showed extensive heterotopic ossifications. Retrospectively, alkaline phosphatase levels were elevated. It is likely that local and systemic factors contribute to the development of heterotopic ossifications. Early diagnosis is important to provide complementary non-pharmacological interventions (gentle passive mobilization) and medication (non-steroidal anti-inflammatory drugs, such as indomethacin). If pain and limited joint mobility remain present, surgical removal of ectopic bone could be considered. Future trials are needed to systematically map the prevalence of heterotopic ossifications in COVID-19 patients who were admitted to the Intensive Care Unit, andto evaluate whether prophylactic treatment with non-steroidal anti-inflammatory drug is of relevance.

A Comparison of 2 Anterior Hybrid Techniques for 3-Level Cervical Degenerative Disc Disease.

BACKGROUND Novel hybrid surgical techniques that incorporate anterior cervical discectomy and fusion with total disc replacement are widely used. Based on the number of implanted discs, 3-level hybrid surgery can be classified as single fusion combined with double replacement and single replacement combined with double fusion. Few studies to date have directly compared these hybrid techniques. The present study compared the clinical and radiological outcomes of these methods and assessed their characteristics and benefits. MATERIAL AND METHODS Clinical and radiological outcomes were retrospectively evaluated in 64 consecutive patients who underwent 3-level hybrid surgery by single fusion combined with double replacement or single replacement combined with double fusion. RESULTS Significant differences between the 2 groups were observed in postoperative range of motion of C2-C7. C2-C7 cervical lordosis assessed preoperatively and at final follow-up differed significantly in patients who underwent single replacement combined with double fusion. This group showed a higher incidence of heterotopic ossification than patients who underwent double replacement combined with single fusion. CONCLUSIONS Both types of hybrid surgery are safe and effective in treating 3-level cervical degenerative disc diseases. Single replacement combined with double fusion showed greater accuracy in correcting cervical lordosis, but was associated with a higher incidence of heterotopic ossification. In contrast, single fusion combined with double replacement was superior in maintaining cervical range of motion.

Association of cervical sagittal alignment with adjacent segment degeneration and heterotopic ossification following cervical disc replacement with Prestige-LP disc.

PURPOSE: Cervical sagittal balance plays important roles in transmitting the load of the head and maintaining global spinal balance. This study aimed to identify the association of cervical sagittal alignment with adjacent segment degeneration (ASD) and heterotopic ossification (HO) after Prestige-LP cervical disc replacement (CDR). METHODS: We enrolled 132 patients who underwent one-level Prestige-LP CDR with 2-10 years of follow-up. Cervical sagittal alignment parameters, including the degree of C2-C7 lordosis (CL), functional spinal unit angle (FSUA), sagittal vertical axis (SVA),, and T1 slope (T1s), were measured. ASD and HO were evaluated at the last follow-up. Unpaired t tests and logistic regression analysis were used to identify the associations of cervical sagittal alignment with ASD and HO. RESULTS: We found that patients who developed ASD showed significantly lower FSUA (2.1° vs. -1.4°, p < 0.001) and T1s values (28.4° vs. 25.5°, p = 0.029) after surgery. Similarly, the postoperative CL was significantly better in patients without ASD or HO (18.0° vs. 14.4°, p = 0.043). The decrease in the T1s at the last follow-up was significantly larger in the patients with ASD (-11.0° vs. -3.2°, p = 0.003), HO (-6.7° vs. -2.7°, p = 0.050), and ASD or HO (-7.0° vs. -0.8°, p < 0.001) than in those without ASD or HO. Multivariate logistic regression analysis showed that both the FSUA and T1s are associated with ASD and that the degree of CL is associated with postoperative complications. CONCLUSION: The results imply that maintaining cervical sagittal alignment after Prestige-LP CDR is important.

Painful Snapping of Thumb Caused by a Displaced Non-Union Fragment from the Trapezium: A Case Report.

There are only a few reports regarding snapping thumb caused by the pathology of the extensor tendon. We report a rare case of snapping thumb caused by a displaced non-union fragment from the trapezium in a 54-year-old man treated with the surgical resection. The intraoperative findings and the outcome are described.

When the Nervous System Turns Skeletal Muscles into Bones: How to Solve the Conundrum of Neurogenic Heterotopic Ossification.

PURPOSE OF REVIEW: Neurogenic heterotopic ossification (NHO) is the abnormal formation of extra-skeletal bones in periarticular muscles after damage to the central nervous system (CNS) such as spinal cord injury (SCI), traumatic brain injury (TBI), stroke, or cerebral anoxia. The purpose of this review is to summarize recent developments in the understanding of NHO pathophysiology and pathogenesis. Recent animal models of NHO and recent findings investigating the communication between CNS injury, tissue inflammation, and upcoming NHO therapeutics are discussed. RECENT FINDINGS: Animal models of NHO following TBI or SCI have shown that NHO requires the combined effects of a severe CNS injury and soft tissue damage, in particular muscular inflammation and the infiltration of macrophages into damaged muscles plays a key role. In the context of a CNS injury, the inflammatory response to soft tissue damage is exaggerated and persistent with excessive signaling via substance P-, oncostatin M-, and TGF-ß1-mediated pathways. This review provides an overview of the known animal models and mechanisms of NHO and current therapeutic interventions for NHO patients. While some of the inflammatory mechanisms leading to NHO are common with other forms of traumatic and genetic heterotopic ossifications (HO), NHOs uniquely involve systemic changes in response to CNS injury. Future research into these CNS-mediated mechanisms is likely to reveal new targetable pathways to prevent NHO development in patients.

Immobilization after injury alters extracellular matrix and stem cell fate.

Cells sense the extracellular environment and mechanical stimuli and translate these signals into intracellular responses through mechanotransduction, which alters cell maintenance, proliferation, and differentiation. Here we use a mouse model of trauma-induced heterotopic ossification (HO) to examine how cell-extrinsic forces impact mesenchymal progenitor cell (MPC) fate. After injury, single-cell (sc) RNA sequencing of the injury site reveals an early increase in MPC genes associated with pathways of cell adhesion and ECM-receptor interactions, and MPC trajectories to cartilage and bone. Immunostaining uncovers active mechanotransduction after injury with increased focal adhesion kinase signaling and nuclear translocation of transcriptional coactivator TAZ, inhibition of which mitigates HO. Similarly, joint immobilization decreases mechanotransductive signaling, and completely inhibits HO. Joint immobilization decreases collagen alignment and increases adipogenesis. Further, scRNA sequencing of the HO site after injury with or without immobilization identifies gene signatures in mobile MPCs correlating with osteogenesis, and signatures from immobile MPCs with adipogenesis. scATAC-seq in these same MPCs confirm that in mobile MPCs, chromatin regions around osteogenic genes are open, whereas in immobile MPCs, regions around adipogenic genes are open. Together these data suggest that joint immobilization after injury results in decreased ECM alignment, altered MPC mechanotransduction, and changes in genomic architecture favoring adipogenesis over osteogenesis, resulting in decreased formation of HO.

Post-stroke bilateral heterotopic ossification: An acute problem with long-lasting consequences.

Heterotopic ossification (HO) is a complication of injury to the central nervous system in which production of lamellar bone within the soft tissues occurs resulting in pain, reduced range of motion (ROM) and loss of functional capacity. Heterotopic ossification is rarely seen in stroke patients and mostly affects the paretic side. In this article, we present a case of established bilateral HO of the hips soon after stroke onset. A 77-year-old female patient with a five-month history of stroke presented to our rehabilitation clinic. Physical examination revealed sensorimotor aphasia, right-sided hemiplegia, bilateral painful limited ROM of the hips and left knee contracture. An anteroposterior X-ray of the pelvis revealed previously undiagnosed bilateral HO of the hips. The patient and her relatives declined operative interventions. The patient was discussed in the departmental meeting and it was agreed that she would not be able to partake in an active inpatient rehabilitation program. She was discharged with a home exercise plan. This case highlights the importance of HO, of both the paretic and non-paretic side, being included in the differential diagnosis of post-stroke patients presenting with joint pain and reduced ROM, both acutely and in the long-term. This may aid the timely diagnosis and management of HO, a pathology which has detrimental effects on functionality.

ßig-h3 enhances chondrogenesis via promoting mesenchymal condensation in rat Achilles tendon heterotopic ossification model.

Heterotopic ossification (HO) is a poorly characterized disease with ectopic bone formation in the musculoskeletal soft tissues. HO is widely considered as a tissue repair process goes away, with endochondral ossification to be the major pathological basis. The molecular mechanism of how the resident/recruited progenitor cells for tissue regeneration error differentiated into the chondrocytes remains unknown. Here, we found Transforming Growth Factor B Induced Gene Human Clone 3 (ßig-h3) was highly expressed in the inflammation and chondrogenesis stages of a heterotopic ossification model after rat Achilles tendon injury, as well as upon chondrogenic differentiation conditions in vitro. ßig-h3 functioned as an extracellular matrix protein, which was induced by TGFß signaling, could bind to the injured tendon-derived stem cells (iTDSCs) and inhibit the attachment of iTDSCs to collagen I. Exogenous ßig-h3 was also found able to accelerate the process of mesenchymal condensation of cultured iTDSCs and promote chondrogenic differentiation in vitro, and additional injection of iTDSCs could promote endochondral ossification in Achilles tendon injury model. Taken together, ßig-h3 might function as an adhesion protein that inhibited the attachment of iTDSCs to collagen I (the injury site) but promoted the attachment of iTDSCs to each other, which resulted in promoting chondrogenic differentiation.

Early resection of ectopic bone in patients with heterotopic ossification about the hip after trauma.

OBJECTIVES: Heterotopic ossification (HO) is a common complication in patients who have sustained high-energy trauma to the hip region. Traditionally, resection is performed after ectopic bone maturation. We hypothesized that early HO resection in patients with hip ankylosis after trauma can be performed with little chance of recurrence. DESIGN: Retrospective clinical cohort. SETTING: Level I Trauma Center PATIENTS/PARTICIPANTS: 14 patients with resection of HO about the hip performed by the senior author during a six-year period. INTERVENTION: Early resection of Brooker Class III or IV HO. MAIN OUTCOME MEASUREMENTS: The original injuries, risk factors for HO, post-traumatic clinical course including the workup for HO, times from fixation to resection, surgical approach, and complications were recorded. Records were reviewed to document pre and postoperative hip motions. Pre and post-operative x-rays and CT scans were reviewed to classify the HO and localize the ectopic mass. RESULTS: Mean injury to resection interval was 6.8-months. Nine of 14 (64%) patients were followed for a mean of 32.9-months post-resection. Indications for resection included pain, stiffness, and evolving sciatic nerve lesions. Risk factors were male gender, brain injury, and extended iliofemoral and Kocher-Langenbeck surgical approaches. Complications included gluteal vein laceration, draining wounds, and recurrence. Mean flexion-extension arc of motion was 18° (range = 0-70°) preoperatively, 100° (range = 85-125°) intra-operatively, and 94° (range = 20-110°) at final follow-up. HO recurred in nine patients; functionally significant in one. CONCLUSION: Early resection of HO around the hip may be performed with little chance of symptomatic recurrence. LEVEL OF EVIDENCE: This is a Level IV retrospective case series.

Is Anterior Bone Loss the Opposite of Anterior Heterotopic Ossification in Prestige-LP Cervical Disc Replacement?

BACKGROUND: Heterotopic ossification (HO) and anterior bone loss (ABL) are 2 complications in cervical disc replacement (CDR), which have impacts on the clinical outcomes. Physiologically, bone formation (HO) and bone loss are 2 sides of bone remodeling. However, clinically, some patients experienced anterior HO (AHO) after CDR, whereas other patients experienced ABL. Is there any factor in determining the fate of the vertebral bone in the anterior region? Is ABL the opposite of AHO? This study aims to answer these questions. METHODS: Seventy patients with 1-level Prestige-LP CDR were retrospectively reviewed and were divided into an AHO group or ABL group. Radiologic outcomes, including cervical lordosis, sagittal vertical axis, functional spine unit angle, disc angle, range of motion, implant migration, subsidence, and adjacent segment degeneration were evaluated. Patient-reported clinical outcomes were also evaluated. RESULTS: AHO group showed significantly lower disc angle after surgery (0.9° ± 4.2°), compared with ABL group (6.7° ± 4.7°) (P < 0.001). The preoperative segmental range of motion was significantly higher in the AHO group (10.2° ± 3.3°) than in the ABL group (8.2° ± 3.7°) (P = 0.042). No correlation was observed between clinical outcomes and the presence of anterior bone remodeling. Both groups maintained cervical alignment and functional spine unit angle during long-term follow-up. No significant difference was found in the end plate preparation, implant subsidence, migration, or adjacent segment degeneration rate between the 2 groups. CONCLUSIONS: The differences in the disc angle showed the role of mechanical load in the anterior bone remodeling. Combined the results with the basic concepts of bone remodeling, ABL may be the opposite of AHO.

Heterotopic Ossification After an Achilles Tendon Rupture Cannot Be Prevented by Early Functional Rehabilitation: A Cohort Study.

BACKGROUND: Tendon loading might play a role in the development of heterotopic ossification after Achilles tendon ruptures. Early heavy loading on a healing tendon in animals has been shown to prolong the proinflammatory response, and inflammatory cells are thought to drive heterotopic ossification formation. Taken together, this suggests that early rehabilitation might influence heterotopic ossification development. QUESTIONS/PURPOSES: The purposes of this study were to investigate (1) whether the presence of heterotopic ossification after Achilles tendon ruptures influences clinical outcome and (2) whether early mobilization or weightbearing prevents the development of heterotopic ossification. METHODS: This was a retrospective analysis of 69 patients from a previous clinical trial. All patients were treated surgically, but with three different early rehabilitation protocols after surgery: late weightbearing and ankle immobilization, late weightbearing and ankle mobilization, and early weightbearing and ankle mobilization. Plain radiographs taken 2, 6, 12, 26, and 52 weeks postoperatively were analyzed for heterotopic ossification, which was detected in 19% of patients (13 of 69) at 52 weeks. Heterotopic ossification was measured, scored, and correlated to clinical outcomes; heel-raise index (HRI), ankle joint ROM, tendon strain, Achilles tendon rupture score (ATRS), and Victorian Institute of Sport Assessment-Achilles (VISA-A) questionnaire scores at 26 and 52 weeks postoperatively. RESULTS: Heterotopic ossification had no adverse effects on patient-reported outcomes (ATRS or VISA-A), tendon strain, or ROM. In fact, patients with heterotopic ossification tended to have a better HRI at 52 weeks compared with patients without (mean difference 14% [95% CI -0.2 to 27]; p = 0.053). Neither the occurrence (heterotopic ossification/no heterotopic ossification) nor the heterotopic ossification severity (ossification score) differed between the three rehabilitation groups. Seventeen percent of the patients (four of 24) with early functional rehabilitation (early weightbearing and ankle joint mobilization exercise) had heterotopic ossification (score, 2-3) while late weightbearing and immobilization resulted in heterotopic ossification in 13% of the patients (score, 3-4). CONCLUSIONS: Heterotopic ossification occurs relatively frequently after Achilles tendon ruptures but appears to have no adverse effects on functional outcomes. Furthermore, heterotopic ossification develops during the first 6 weeks after rupture, and weightbearing or ankle-joint mobilization does not prevent this from occurring. LEVEL OF EVIDENCE: Level III, prognostic study.

Heterotopic ossifications and Charcot joints: Congenital insensitivity to pain with anhidrosis (CIPA) and a novel NTRK1 gene mutation.

Congenital insensitivity to pain with anhidrosis (CIPA), also known as hereditary sensory and autonomic neuropathy type IV (HSAN-IV), is a rare and severe autosomal recessive disorder. We report on an adult female patient whose clinical findings during childhood were not recognized as CIPA. There was neither complete anhidrosis nor a recognizable sensitivity to heat. Tumorlike swellings of many joints and skeletal signs of Charcot neuropathy developed in adolescence which, together with a history of self-mutilation, led to a clinical suspicion of CIPA confirmed by identification of a novel homozygous variant c.1795G > T in the NTRK1 gene in blood lymphocytes. Both parents were heterozygous for the mutation. The variant predicts a premature stop codon (p.Gly599Ter) and thus represents a pathogenic variant; the first reported in the Southeastern European population.

Assessment of surgical treatment of Eagle's syndrome.

INTRODUCTION: The aim of the study was to assess the effectiveness of surgical treatment of patients with Eagle's syndrome, taking into account both early and late results. MATERIAL AND METHODS: The study group consisted of 15 patients who underwent resection of the styloid process due to Eagle syndrome in the period of 2005-2017. During the follow-up visit, the patients were asked to fill in a post-operative questionnaire that compared the pre-operative symptoms and their severity with the patients' current health condition. The VAS pain scale was used to assess each symptom, and the Laitinen scale was used to assess the quality of life. Data from patients' medical records were also included. The results of the surveys were subjected to statistical analysis. RESULTS: The study showed that in 11 out of 15 cases there was a significant improvement in the level of pain (70.5% on average) and an improvement in quality of life (on average 65%) comparing to the pre-operative condition. The Wilcoxon test for binding pairs, the Mann-Whitney test, the Kruskal-Wallis test and the Spearman correlation coefficient were used in the statistical analysis. There were statistically significant correlations between the recorded improvement rate and the length of the resected styloid process and its setting. DISCUSSION: The study proved that resection of prolonged styloid process from extraoral approach in most cases is an effective method of treatment of Eagle syndrome, that carries low risk of complications.

Anterior elbow dislocation without fracture in an adult: a rare injury pattern.

Anterior elbow dislocation without periarticular fracture (simple dislocation) is an extremely rare injury and is usually caused by distraction or torsional forces. It is important to look for associated ligamentous and musculotendinous injuries in this pattern. We report an elderly patient who sustained simple anterior dislocation of the elbow and in whom successful closed reduction could be achieved. Reduction by closed method is possible if we know the exact mechanism of elbow injury. Despite the presence of medial collateral ligament injury, he was managed non-operatively and had full functional recovery. Checking for joint stability and collateral ligaments after reduction and getting additional radiological investigations help in better treatment planning. Early protected active mobilisation should be initiated to achieve better functional results.

Risk factors of cage subsidence after removal of localized heterotopic ossification by anterior cervical discectomy and fusion: A retrospective multivariable analysis.

The purpose of the study was to identify risk factors of cage subsidence and evaluate surgical outcome by at least 12 months postoperative follow-up.We retrospectively investigated 113 consecutive patients who underwent anterior surgery to relieve spine cord compression resulted from localized heterotopic ossification, from July, 2011 to February, 2016. We divided the patients into 2 groups: cage subsidence <2 mm group and ≥2 mm group. According to magnetic resonance imaging (MRI), the severity of increased signal intensity (ISI) was classified into grade 0, 1, and 2. Clinical outcome was assessed by the Japanese Orthopedic Association (JOA) scoring system. Logistic regression analysis and receiver-operating characteristic (ROC) curve were utilized for predicting risk factors of cage subsidence, and the recovery rate was evaluated by Kruskal-Wallis test or Mann-Whitney U test.Logistic regression with cage subsidence as the dependent variable showed independent risks associated with a cervical sagittal malalignment (odds ratio [OR] 11.23, 95% confidence interval [CI] 3.595-35.064, P < .001), thoracic 1 (T1) slope angle (OR 1.59, 95% CI 1.259-1.945, P < .001), and excisional thickness (OR 2.38, 95% CI 1.163-4.888.0, P = .018). The cut-off values of T1 slope and excisional thickness were 19.65 angle and 3.7 mm, respectively. Patients with high occupying ratio (P = .001) and high ISI grade (P = .012) are more likely to occur lower recovery rate.Patients with high T1 slope angle or preoperative kyphotic deformity should avoid excessive removal of endplate and vertebral body so as to reduce the occurrence of cage subsidence. Poor outcome was closely related to cervical sagittal malalignment and higher ISI grade.

Heterotopic Ossification Requiring Revision Surgery for Elbow Contracture After Tension Band Wiring for an Isolated Olecranon Fracture A Case Report.

Olecranon fractures are common trauma presentations, and generally good or excellent functional outcomes are expected after surgical treatment. The development of heterotopic ossification (HO) is a well-known complication, leading to restricted motion, subsequent joint contractures, and marked functional limitation of the upper extremity. Whereas most olecranon fractures complicated by HO have less extensive ossification and limited clinical implications, we report a rare case of HO that required revision surgery for elbow contracture after tension band wiring for an isolated olecranon fracture. Our findings indicate that even patients with isolated olecranon fractures should be notified about the potential risk of HO development, which could result in restricted motion and subsequent joint contractures. The risk factors associated with the development of HO after elbow trauma should be recognized during surgical treatment for olecranon fracture. Fractures of the olecranon are common trauma presentations. 1 Most olecranon fractures are treated surgically, and good or excellent functional outcomes are expected after surgical treatment.1 The development of heterotopic ossification (HO) is a well-known complication after elbow trauma that causes restricted motion, subsequent joint contractures, and marked functional limitation of the affected upper extremity.2 The severity of HO is related to the nature of the injury. Most olecranon fractures complicated by HO have less extensive ossification, and the clinical implications of this type of injury are limited.3 We report a rare case of HO in which revision surgery for the treatment of elbow contracture was required after an isolated olecranon fracture.